In recent years, concern about a multifaceted use of renewable energy and an energy-saving society has been increasing, and introduction of a smart meter system that enables visualization of power consumption by an automated meter reading, control of supply and demand, and the like has been promoted. In such a smart meter system, a wireless communication network is formed by, for example, adding a wireless communication terminal that has a wireless communication unit to an electrical-power meter arranged per consumer, to organically connect to a backbone network of an electric power company or the like, thereby configuring such that centralized management and control by an operator are enabled.
Because the wireless communication terminal is arranged per consumer as described above, the quantity thereof is huge, and there is a task of optimization to reduce power consumption for suppressing the amount of electricity usage amount to be added and to achieve low prices to reduce the introduction cost.
Moreover, when a wireless mesh communication system is adopted as a wireless communication system that is comparatively compatible with the smart meter system, it is supposed to set the transmission interval of a firmware delivery packet comparatively long because of the radio wave interference in the system, and to increase distribution time. Therefore, it is desirable that the use efficiency of the communication resources be improved.
Such a wireless communication terminal has software or firmware (hereinafter, simply “software”) to perform various kinds of processing an control to implement a wireless communication function or an additional function installed therein, and it is supposed to update the software to add new functions, solve a problem such as bugs, and the like.
As a related technique relating to software update for a wireless communication terminal, for example, in a technique disclosed in Japanese Laid-open Patent Publication No. 2003-198450, a system and a method are proposed that aim to suppress a load on an operator to a minimum and to maintain high usage efficiency of a wireless source by going through such steps that a wireless communication base station notifies a wireless communication terminal of software update information, the wireless communication terminal that receives the update information performs determination about the update information, and when update is supposed, receives software of an update object that is distributed by broadcasting from the wireless communication base station separately, by controlling a software receiving unit in the terminal itself to update the software.
According to the above related technique, a wireless communication terminal receives update information that is transmitted separately from distribution of software and determines whether software update is supposed. Accordingly, if the update information is unable to be received, whether update is supposed is not determined even if software distribution data requiring update is received and the data is to be discarded. Therefore, there has been a problem that distribution efficiency of software is lowered.